Question

The zinc/silver oxide cell is used in hearing aids and electric watches. The following reactions take place: `ZntoZn^(2+)+2e^(-),E^(@)=0.76V`
`Ag_(2)O+H_(2)O+2e^(-)to2Ag+2OH^(-),E^(@)=0.344V`
(a) What is oxidized and reduced?
(b) Find `E^(@)` of the cell and `DeltaG` in joules.

Answer 1

(a) Zn is oxidized and `Ag_(2)O` is reduced (as `Ag^(+)` ions change into Ag)
(b) `E_(cell)^(@)=E_(Ag_(2)O//Ag)^(@)(Red)+E_(Zn//Zn^(2+))^(@)(Ox)=0.344+0.76=1.104V`
`DeltaG=-nFE_(cell)^(@)=-2xx96500xx1.104J=-2.13xx10^(5)J`.